Please help me, I don't bite. 3.

Answer:

The initial temperature of the brass sample is 90.1°C

Note: The question is incomplete. A similar but complete question is given below :

A 52.9g sample of brass, which has a specific heat capacity of 0.375·J·g−1°C−1, is put into a calorimeter (see sketch at right) that contains 100.0g of water. The temperature of the water starts off at 15.0°C. When the temperature of the water stops changing it's 18.4°C. The pressure remains constant at 1 atm. Calculate the initial temperature of the brass sample. Be sure your answer is rounded to 2 significant digits.

Explanation:

Assuming that the calorimeter is an isolated system and that no heat is lost from the calorimeter. The total heat in the system is the sum of the heat content of the brass and that of water

Total heat lost by the brass = heat gained by the water

The quantity of heat lost or gained, Q = mcΔT

Where m = mass of the substance, c = specific heat capacity of substance, ΔT = temperature change

Heat gained by water is positive while heat lost by brass is negative

mass of brass = 52.9 g, specific heat capacity of brass = 0.375·J·g−1°C−1, ΔT = (18.4 - t °C; where t is the initial temperature), mass of water = 100.0 g, specific heat capacity of water = 4.186 J/g°C, ΔT = = 18.4 - 15.0 = 3.4 °C

Heat lost by brass z= - [ 52.9 × 0.375 × (18.4 - t)] = -365.01 + 19.8375t

Heat gained by water = 100 × 4.186 × 3.4 = 1423.24

Equating heat lost by brass to heat gained by water

-365.01 + 19.8375t = 1423.24

19.8375t = 1423.24 + 365.01

19.8375t = 1788.25

t = 90.1° C

Therefore, the initial temperature of the brass sample is 90.1°C

Answer:

B

Explanation:

It's the same substance but in different states.

HETEROGENEOUS mixtures contain substances that are

not uniform in composition. The parts in the mixture can be separated by physical means.

Answer:

104.8 g

Explanation:

From the question given above, the following data were obtained:

Initial temperature of copper (T꜀) = 275.1 °C

Mass of water (Mᵥᵥ) = 272 g

Initial temperature of water (Tᵥᵥ) = 21 °C

Equilibrium temperature (Tₑ) = 29.7 °C

Mass of copper (M꜀) =?

NOTE:

Specific heat capacity of copper (C꜀) = 0.385 J/gºC

Specific heat capacity of water (Cᵥᵥ) = 4.184 J/gºC

Finally, we shall determine the mass of the copper in the sample. This can be obtained as follow:

Heat loss by copper = Heat gained by water

M꜀C꜀(T꜀ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)

M꜀ × 0.385 (275.1 – 29.7) = 272 × 4.184(29.7 – 21)

M꜀ × 0.385 × 245.4 = 1138.048 × 8.7

M꜀ × 94.479 = 9901.0176

Divide both side by 94.479

M꜀ = 9901.0176 / 94.479

M꜀ = 104.8 g

Thus, the mass of the copper in the sample is 104.8 g

Answer:

D. Two scientists may have different underlying assumptions that lead them to different conclusions about the same thing.

Explanation:

It's all about how a person analyzes data. Some do it mathmatically while others do it logically. By doing it different ways, you may still come to the same conclusion, despite working at the problem in a different way.

Answer:

C₆H₆

Explanation:

Each border of the figure represents 1 atom of carbon. We have 6 borders = 6 atoms of carbon.

Each atom of carbon form 4 bonds. All the carbons are doing a double bond and a single bond with other carbons. That means are bonded 3 times. The other bond (That is not represented in the figure. See the image) comes from hydrogens. As we have 6 carbons that are bonded each 1 with one hydrogen. There are six hydrogens and the molecular formula is:

This structure is: Benzene

Answer:

Find the definition below.

Explanation:

A standard cell is a group of transistors that have a regular electromotive force flowing through them. They follow either the boolean function or the storage function. A technology library that is made up of a collection of standard cells can be used to facilitate the placement, routing, and synthesis of the Application-specific Integrated Circuit (ASIC).

Electronic Design Automation is an example of an apparatus that implements this functionality.

Answer:

a. the proportion of elements to compounds is constant.

Answer:

Please find the complete question and its solution file in the attachment.

Explanation:

Answer:

Scientific method.

Explanation:

Scientific method is the way taken to acquire scientific knowledge. It includes experiments, statistical analysis of existing data, and all kinds of observations of the world around us, while theoretical research is based on deriving certain theories about the world from basic principles, in a mathematical or logical way. The scientific method applies to both types of research, and emphasizes that scientific research is objective, that it can be verified by other scientists, and that knowledge is not acquired without context, but in a way that leads to a greater understanding of previous research and the world. we live in. To contribute to this, researchers are expected to clearly record both their findings and the methods they use to arrive at the results.

Answer:

Each of the following reactions was in equilibrium when the pressure of their containers was doubled. Chose which way the reaction shifted after the pressure change:

2NH3 (g)->N2(g) +3H2(g)

2Na3 PO4 (aq) + 3CaCl2 (aq) -> Ca3 (PO4 )2 (s) + 6NaCl(aq)  

2CO(g)+O2 (g)->2CO2 (g)  

2HI(g) -> H2(g) + I2(g)

Explanation:

Effect of pressure on equilibrium:

When pressure is increased on an equilibrium system,then equilibrium will shift in such a direction towards less number of moles of substrates.

For the first system,

2NH3 (g)->N2(g) +3H2(g)

increase in pressure,shifts the equilibrium towards the left side that is the formation of ammonia is favored.

For the second reaction:

2Na3 PO4 (aq) + 3CaCl2 (aq) -> Ca3 (PO4 )2 (s) + 6NaCl(aq)

The quilibrium will shift towards right.

Becuase right side less number of moles of substrates are there.

2CO(g)+O2 (g)->2CO2 (g)

For this system,the equilibrium will shift towards right side that is formation of CO2 gas is favored.

For the last system,

2HI(g) -> H2(g) + I2(g)

there is no effect of pressure.

Becuase the number of moles of substrates are same on both sides.

Answer:

a hydrogen bond between the hydrogen of water and the nitrogen of the amine

a hydrogen bond between the oxygen of water and a hydrogen from the -NH2 group

Explanation:

A hydrogen bond is formed between molecules in which hydrogen is bonded to a highly electronegative element.

In amines, hydrogen is bonded to nitrogen while in water, hydrogen is bonded to oxygen. Both are highly electronegative elements hence hydrogen bonding is possible between amines and water.

This hydrogen bond may involve;

The hydrogen of water and the nitrogen of the amine

Or

The oxygen of water and a hydrogen from the -NH2 group

Answer:

A molecule of sucrose (C12H22O11) has 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.

Explanation:

if this does not help let me know :)

There are   1.4376  × 10²⁶ carbon atoms in 15 lbs of sugar (C12H22O11).

From the given information,

Using the standard conversion method;

1 lbs = 453.592 gram

∴

15 lbs = (453.592 gram × 15 lbs/1 lbs)

= 6803.88 grams

Now, we will need to determine the molar mass of the sugar compound C12H22O11.

Molar mass of C12H22O11 =  (12 × 12) +(1 × 22) + (16 × 11)

Molar mass of C12H22O11 = 144 + 22 + 176

Molar mass of C12H22O11 = 342 g/mol

Using the relation:

[tex]\mathbf{Number \ of \ moles = \dfrac{mass}{molar \ mass}}[/tex]

Number of moles = [tex]\dfrac{6803.88 }{ 342}[/tex]

Number of moles of C12H22O11   = 19.894 moles

Since we've known the number of moles present in C12H22O11, the next thing to do is determine the number of molecules of sugar by using Avogadro's constant:

i.e.

number of moles of sugar = [tex]19.894 moles \times \dfrac{6.023 \times 10^{23}}{mol}[/tex]

= 1.198 × 10²⁵ molecules of C12H22O11

Now to determine the number of carbon atoms in 15 lbs, we have:

= number of carbon atoms × amount of molecules

= 12 × 1.198 × 10²⁵ carbon atoms

= 1.4376  × 10²⁶ carbon atoms

Therefore, we can conclude that there are  1.4376  × 10²⁶ carbon atoms present in 15 lbs of sugar, C12H22O11

Learn more about atoms here:

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Answer:

Huh!?

Explanation:

explain me please

Answer:

The correct answer is "-268.667°C".

Explanation:

Given:

Temperature,

= 4.483 K (below)

Now,

The formula of temperature conversion will be:

⇒ [tex]T(^{\circ} C)=T(K)-273.15[/tex]

By putting the values, we get

⇒            [tex]=4.483-273.15[/tex]

⇒            [tex]=-268.667^{\circ} C[/tex]

Thus the above is the correct answer.

Answer:

D) caring capacity

Explanation:

Answer:

D)

Explanation:

The largest population that an environment can support is by definition a carrying capacity

Answer:

Indicate how the concentration of each species in the chemical equation will change to reestablish equilibrium after reactant or product is added.

[tex]2CO(g) + O2(g) <=> 2CO2[/tex]

Explanation:

When the reactants concentration increases, then the equilibrium will shift towards products and when the concentration of products increases, then equilibrium will shift towards reactants.

So, increases in concentration of carbon monoxide (CO) shifts the equilibrium to favor the formation of carbondioxide.

Similarly increase in concentration of oxygen also favor the formation of product carbon dioxide.

Increase in concentration of CO2 favors the formation of CO and O2.

Decrease in product concentration also favors the formation of product.

Decrease in reactant concentration favors the formation of reactants only.

Explanation:

here is your answer

hope this will help you

Answer:

643(%=:(¥75 )(:7$"8"),"7$"()9_/"¥?:

Answer:

Percent yield = 48.3%

Explanation:

The reaction is:

CCl₄  +  2HF → CF₂Cl₂ + 2HCl

1 mol of CCl₄ reacts with 2 moles of hydrofluoric acid in order to produce 1 mol of CF₂Cl₂ and 2 moles of hydrogen chloride.

HF is in excess, so the limiting reagent is the CCl₄.

We convert mass to moles:

32.9 g . 1mol / 153.8g = 0.214 moles

Ratio is 1:1. In conclussion: 0.0813 moles of CCl₄ can produce 0.0813 moles of CF₂Cl₂. We convert moles to mass, to determine the theoretical yield:

0.214 mol . 120.91g /mol = 25.8 g

Percent yield = (Yield produced /Theoretical yield) . 100

Percent yield = (12.5 g/ 25.8g) . 100 = 48.3%

The question is incomplete, the complete question is;

. A chemist determined by measurements that 0.015 moles of hydrogen chloride participate in a chemical reaction. Calculate the mass of hydrogen chloride that participates Round your answer to 2 significant digits. x S. ?

Answer:

0.54 g

Explanation:

Recall that;

Number of moles = mass/molar mass

Molar mass of HCl =36.5 g/mol

Mass= number of moles × molar mass

Mass= 0.015 moles × 36 g/mol

Mass= 0.54 g

Answer:

The correct options are a, b and d

Explanation:

A catalyst is a substance that increases the rate of a chemical reaction by reducing the activation energy. Le Catelier's  principle explains how a substance or an "action" can affect a reaction in equilibrium.

The principle states that when a change is made to the conditions of a reacting system at equilibrium, the position of the equilibrium moves to counteract the change made. These changes are change in temperature, pressure, volume and/or concentration. These changes will either cause the equilibrium to shift forward or backward.

However, the presence of a catalyst DOES NOT affect a chemical equilibrium/equilibrium constant nor does it affect the reaction quotient because the same amount of reactants and products are available just as in uncatalyzed reaction except that the reaction proceeds faster (which does not affect equilibrium).

The rate of reaction is given as the time required by the reactant to convert into the product. The addition of catalyst increases the rate of reaction, while the reaction quotient and the equilibrium remain unaffected.

A catalyst is a chemical or compound that adds to the reaction and lowers the activation energy by providing an alternative path to the reaction.

The catalyst takes part in the reaction but did not consume in the chemical reaction.

The equilibrium and the reaction quotient are dependent on the conversion of the reactant to the product. The catalyst is not used in the reaction and thus did not affect the reaction quotient or the equilibrium.

Hence, options A, B, and D are correct for the use of catalysts in the chemical reaction.

Learn more about catalysts, here:

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Answer:

neon

Explanation:

The octet rule states that atoms of elements are stable when they possess 8 electrons on their outermost shell.

Hence, atoms of elements participate in chemical reactions in order to attain this octet structure (eight electrons in the outermost shell).

Neon is a noble gas and already has eight electrons in its outermost shell. Hence, neon is least likely to obey the octet rule.

Answer:

According to the four quantum numbers; magnetic quantum number is the same as angular momentum quantum number. so the answer is 5

Explanation:

for d subshell angular momentum "d" is assigned a value of : m= 2(range from negative to positive i.e, -2 to 2) so we have [ -2, -1 ,0, 1 , 2] which concludes to 5.

Answer:

2.33 mol C

Explanation:

Step 1: Write the balanced generic chemical equation

3 A ⟶ C + 4 D

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of A to C is 3:1.

Step 3: Calculate the number of moles of C produced from 7 moles of A

We will use the previously established molar ratio.

7 mol A × 1 mol C/3 mol A = 2.33 mol C

Answer:

Option a.

Explanation:

To determine which is a balanced chemical reaction, see the stoichiometry.

Stoichiometry coefficients are the numbers that appear before the compounds. These numbers indicate moles of substance.

Notice that the number of elements must be the same in both sides of the equation.

In this case, option a is the balanced chemical reaction.

8HCl + 2KMnO₄ → 3Cl₂ + 2MnO₂ + 4H₂O + 2KCl

8 moles of HCl react to 2 moles of potassium permanganate in order to produce 2 moles of magnessium dioxide, 3 moles of chlorine, 2 moles of potassium chloride and 4 moles of water.

8 H, 8 Cl, 2 K, 2 Mn and 8 O

Answer:

See explanation

Explanation:

Equation of the reaction;

Na2CO3(aq) + 2HCl(aq) -------> 2NaCl(aq) + H2O(l) + CO2(g)

Number of moles of Na2CO3 = 21.2g/106g/mol = 0.2 moles Na2CO3

Number of moles of HCl = 21.9g/36.5g/mol = 0.6 moles of HCl

1 mole of Na2CO3 reacts with 2 moles of HCl

0.2 moles of Na2CO3 reacts with 0.2 × 2/1 = 0.4 moles of HCl

Hence Na2CO3 is the limiting reactant

Since there is 0.6 moles of HCl present, the number of moles of excess reagent=

0.6 moles - 0.4 moles = 0.2 moles of HCl

1 mole of Na2CO3 forms 1 mole of water

0.2 moles of Na2CO3 forms 0.2 moles of water

Number of molecules of water formed = 0.2 moles × 6.02 × 10^23 = 1.2 × 10^23 molecules of water

1 mole of Na2CO3 yields 1 mole of CO2

0.2 moles of Na2CO3 yields 0.2 moles of CO2

1 mole of CO2 occupies 22.4 L

0.2 moles of CO2 occupies 0.2 × 22.4 = 4.48 L at STP

Hence;

V1=4.48 L

T1 = 273 K

P1= 760 mmHg

T2 = 27°C + 273 = 300 K

P2 = 760 mmHg

V2 =

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 760 × 4.48 × 300/760 × 273

V2= 4.9 L

The limiting reactant is the reactant that determines the amount of product formed in a reaction. When the limiting reactant is exhausted, the reaction stops.

Answer:

36.55kJ/mol

Explanation:

The heat of solution is the change in heat when the KNO3 dissolves in water:

KNO3(aq) → K+(aq) + NO3-(aq)

As the temperature decreases, the reaction is endothermic and the molar heat of solution is positive.

To solve the molar heat we need to find the moles of KNO3 dissolved and the change in heat as follows:

Moles KNO3 -Molar mass: 101.1032g/mol-

10.6g * (1mol/101.1032g) = 0.1048 moles KNO3

Change in heat:

q = m*S*ΔT

Where q is heat in J,

m is the mass of the solution: 10.6g + 251.0g = 261.6g

S is specififc heat of solution: 4.184J/g°C -Assuming is the same than pure water-

And ΔT is change in temperature: 25°C - 21.5°C = 3.5°C

q = 261.6g*4.184J/g°C*3.5°C

q = 3830.87J

Molar heat of solution:

3830.87J/0.1048 moles KNO3 =

36554J/mol =

Answer:

d. the conjugate base of the weak acid

Explanation:

The strong base (BOH) is completely dissociated in water:

BOH → B⁺ + OH⁻

The resulting conjugate acid (OH⁻) is a weak acid, so it remains in solution as OH⁻ ions.

By other hand, the weak acid (HA) is only slightly dissociated in water:

HA ⇄ H⁺ + A⁻

The resulting conjugate base (A⁻) is a weak base. Thus, it reacts with H⁺ ions from water to form HA, increasing the concentration of OH⁻ ions in the solution.

Therefore, the resulting solution will have a pH > 7 (basic).

ANSWER IS ABOVE

THE METHANOIC ACID

Answer:

Alkaline earth metals or akali metals